Photovoltaic module mounting system

ABSTRACT

A solar array mounting system having unique installation, load distribution, and grounding features, and which is adaptable for mounting solar panels having no external frame. The solar array mounting system includes flexible, pedestal-style feet and structural links connected in a grid formation on the mounting surface. The photovoltaic modules are secured in place via the use of attachment clamps that grip the edge of the typically glass substrate. The panel mounting clamps are then held in place by tilt brackets and/or mid-link brackets that provide fixation for the clamps and align the solar panels at a tilt to the horizontal mounting surface. The tilt brackets are held in place atop the flexible feet and connected link members thus creating a complete mounting structure.

CROSS-REFERENCE TO RELATED APPLICATION

This is a Divisional of U.S. patent application Ser. No. 12/587,970,filed Oct. 15, 2009 now U.S. Pat No. 8,156,697.

This invention was made with U.S. Government support under Contract No.DE-FC36-07GO17047 awarded by the Department of Energy. The Governmenthas certain rights in this invention.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a system for mounting andinstalling photovoltaic solar panels, and more particularly, to aphotovoltaic solar panel to mounting support system providing enhancedattachment features for solar panels having no external frame.

2. Description of the Related Art

With the continual rise in conventional energy costs, photovoltaic solarpanels (“PV panels”) are increasingly becoming cost competitive withother types of energy generation. These PV panel systems are beinginstalled in sites of high energy usage, such as on commercial buildingrooftops, in industrial open areas, and in proximity to substations tiedto the electric grid. These commercial energy systems, or power plants,vary in size but can cover many thousands of square feet on a buildingrooftop and many acres of land when installed on the ground. Roofmounted systems are particularly attractive in that business owners canelect to offset the energy consumption of their facilities through theuse of existing space on the tops of their buildings.

However, such large solar arrays require a sufficiently strong supportstructure to support not only the weight of the array, but to alsoprovide sufficient resistance to wind forces. Tightly spaced panelseffectively form a large surface area, which could result in damage tothe panels, the support structure, or both, under strong windconditions. In addition these systems must accommodate a variety of rooftypes including built-up roof membranes, monolithic, syntheticmembranes, and shingled, mineral surfaces. In order to respond to avariety of roof deck surfaces the mounting structures must provideflexibility in contact elements and attachment systems. These systemsmust balance the benefits of greater weight, or ballast, to resist windforces and the load limits of the buildings upon which they are beingplaced which in many cases were designed to take people walking on thembut not the additional load of a large mechanical array.

In many installations, the solar panels are mounted in a “tilted” orinclined to configuration in order to maximize the effective capture ofsolar radiation, i.e. the solar panels are aligned with the solar angleof incidence. In mounting tilted solar panels, however, the effects ofvarious loads on the mounting surface, such as a roof, must beunderstood. The loads include standing loads and variable loads, alsocommonly called dead loads and live loads, respectively.

Standing loads are the result of the combined weight of the solar panelsand the mounting system. These standing loads are predictable and aretherefore easier to accommodate for during the installation of the solarpanels and the mounting system.

Variable loads on the tilted solar panels are mainly caused byenvironmental conditions, such as wind, rain, snow, hail, etc. Otherpotential environmental hazards include seismic events, temperatureextremes, debris and mold. In order to be able to reliably predict andaccommodate variable loads, these environmental problems have to beunderstood and resolved. The most common and problematic forces arewind-related forces (including hurricanes and tornados), namely lift anddrag forces generated by the wind conditions. A variety of mountingsystems have been commercially available for mounting solar panels,which have attempted to address and mitigate the wind-induced forces.Most prior mounting systems can be divided into three generalcategories: non-tilted solar arrays; enclosed tilted solar arrays; andtilted solar panels with wind deflectors attached to every row.

U.S. Pat. No. 5,746,839 (Dinwoodie) and U.S. Pat. No. 6,570,084(Dinwoodie) are examples of implementations involving non-tilted solarpanels. While non-tilted solar panels do present a lower profile withrespect to wind forces, they are less efficient at converting solarenergy to electrical energy when installed at locations with higherlatitudes. Another disadvantage of a non-tilted system is theaccumulation of dirt, dust, debris and snow on top of the solar panels,which can further reduce the conversion efficiency of the panels.

U.S. Pat. No. 6,968,654 (Moulder) discloses an example of an enclosedtilted solar panel system. While such a design offers advantages such asimproved rigidity, less debris accumulation, and better protection ofelectrical components, an enclosed solar panel system increase the costand weight of the system, is likely to increase wind-induced drag forcesand also significantly reduces beneficial cooling from natural airflow.The additional heat introduced into the panels by the mounting systemresults in lower energy output from the photovoltaic panels.

As shown in U.S. Pat. No. 6,063,996 (Takada), U.S. Pat. No. 6,809,251(Dinwoodie) and U.S. Publication No. 2004/0250491 (Diaz), deflectors maybe installed on the north-facing back of every panel in order to reducethe wind-induced uplift forces, when installed in the northernhemisphere. Disadvantages of such systems include significantlyincreased cost and weight of the installed system. These systems alsoincrease the required labor time for installation in that more partsmust be assembled in order to complete the array. In addition, reducedcooling of the solar panels can also significantly reduce the solarconversion efficiency of the system.

It will also be apparent to one skilled in the art that solar panels ormodules having extruded metal frames will present different challengesin mounting than those that are produced without additional framingelements. The latter type of solar panels are often referred to aslaminates as they are an assembly of one or two sheets of glass alongwith the photovoltaic material and backing sheet materials to form alaminated assembly. The attachment of these frameless modules, orlaminates, is a mechanical challenge often met with the use of clips orhooks that pull one edge of the module into close contact with asupporting structure. Another method of making this connection is toclamp the edge of the module directly and then provide a mountingstructure within the sub-structure of the array to hold the modulemounting clamp.

SUMMARY OF THE INVENTION

In general, the present invention is a solar array mounting systemhaving unique installation, load distribution, and grounding features,and which is adaptable for mounting solar panels having no externalframe. The solar array mounting system includes flexible, pedestal-stylefeet and rigid links connected in a grid formation on the mountingsurface. The photovoltaic modules are secured in place via the use ofattachment clamps that grip the edge of the typically glass substrate.These panel mounting clamps are then held in place by tilt brackets thatprovide fixation for the clamps and align the PV modules at a tilt tothe horizontal mounting surface. The tilt brackets are held in placeatop the flexible feet, which are connected by rigid link members, thuscreating a complete generally planar mounting structure with thecapability of distributing uplift forces along two axes.

More particularly, according to one embodiment of the present invention,the flexible pedestal feet are made of cast, recycled polymers. The linkstructural members are roll formed steel sections that connect at theirends to threaded mounting rods held in place by a steel cruciformsection that is retained in the flexible feet. This overlapping assemblyof cruciform base, flexible foot, roll formed steel link, and threadedrod holding the stack up of components together forms a ‘node’ thatallows for the transfer of uplift and downpush forces born by the systemas a result of wind pressures and suctions.

According to an embodiment of the present invention the panel clampscomprise two parts, an upper and lower section both made of castaluminum. These clamp parts are held together by a threaded fastenerthat is inserted through the top to clamp and threaded into the bottomsection of the clamp. The two parts effectively form two mounting postsfor mounting the clamp on a bracket. Alternately, the mounting post canbe formed as a separate element. The interface between the assembledclamp halves and the module edge is filled by a flexible gasketmaterial. In one embodiment of the invention the flexible gasket is madeof EPDM rubber. This gasket has small, finger like protrusions thatallow for easy insertion onto the module edge while being reversed makesit more difficult to remove them from the module once installed.

In an alternate embodiment, the panel clamp assembly comprises a moldedpolymer resin that is resistant to the effects of sustained outdoorexposure. These polymer parts have the clamping edge of the assemblyover-molded with a flexible rubber material that creates a better gripon the module material which is typically glass.

In another alternate embodiment, the panel clamp comprises an upper andlower section which are snapped or glued together. Each section includestwo slots which align with the mounting openings of a bracket. Aninternal axle (rod) is held in a channel perpendicular to the slots. Thepanel clamp mounts to a bracket such that the axle is held in a mountingbracket positioned through the slots.

A solar panel array system according to the present invention comprisesat least one solar module having no frame wherein the module issupported by clamps attached at the edges of the module in locationssuitable for distributing the loading forces equally. These attachmentclamps are held in place by sheet metal tilt brackets that fix the panelin place and hold it at a predefined tilt angle to the horizontalmounting surface. During installation the panel or panels can beinserted into the tilt bracket with a vertical sliding motion wherebythe modules, with the clamps pre-affixed, can be lowered into positionin the tilt brackets. Once the lower edge of the module is captured bythe tilt brackets the top edge of the module is rotated down to thepreferred tilt angle. In one embodiment of the invention that preferredtilt angle is 2-5 degrees from the horizontal. As the top edge of themodule is lowered to the correct tilt angle the clamps affixed to thetop edge of the module locks into place in the next set of correspondingtilt (or mid-link) brackets. The next panel assembled into the arraywill have its lower edge aligned with the tilt brackets holding theprevious solar modules top edge. In this fashion the same tilt bracketcomponents serve the purpose of holding the top edge of the modulecourse before it and the lower edge of the module course after it. Afterinsertion of the higher edge of the PV module into the top of the tiltbrackets a locking cap is inserted to retain the clamps in the tiltbrackets and hold the sides the tilt bracket parallel to one another.

The flexible foot, cruciform, and link structure provide a compliantmounting structure that can follow the contour of the mounting surfacewhile simultaneously resisting the uplift and down push forces of windloading. The link members, which in one embodiment may be made frompre-galvanized, roll formed steel, span the distance between the rubberpedestal feet. The feet provide the contact point with the mountingsurface. In the case where that mounting surface is a roof top composedof monolithic waterproofing membrane, the rubber feet provide asemi-rigid, non penetrating load-bearing surface for the interfacebetween the roofing material and the solar array. The added benefit ofusing a flexible rubber material is that is generates a high coefficientof friction which in turn makes the system more resistant to slidingmotion created by wind uplift and seismic forces.

In one embodiment of the present invention, the tilt brackets thatsupport the panel mounting clamps are held in place atop the rubber feetvia the anchored ends of the link sections. The link sections come intothe feet at right angles to one another—thus forming an orthogonal gridthat interconnects the panel array in two directions. The links arecaptured at their ends by assembly on to a threaded rod which passesthrough a pre-punched hole in the structural link.

In different variations of the present invention, no mid-link bracketsare utilized, one mid-link bracket is positioned between the feet in afirst direction, or multiple mid-link brackets are located between feetin a first direction.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be readily understood by the followingdetailed description in conjunction with the accompanying drawings,wherein like reference numerals designate like structural elements, andin which:

FIG. 1A is a perspective view of the solar panel mounting systemaccording to an embodiment of the present invention;

FIG. 1B is a side view of the solar panel mounting system of FIG. 1A;

FIG. 1C is a top view of the solar panel mounting system of FIG. 1A;

FIG. 1D is an additional perspective view of the solar panel mountingsystem of FIG. 1A shown with multiple module mounting sectionsinstalled;

FIG. 1E is a perspective view of an alternate embodiment of the solarpanel mounting system, illustrating the components for supporting onepanel;

FIG. 1F is a perspective view of the embodiment of FIG. 1E showing aplurality of panels installed on the system;

FIG. 1G is a perspective view of another embodiment of the solar panelmounting system according to the present invention;

FIG. 2A is a perspective view of one embodiment of the foot, link, tiltbracket and panel clamp assembly according to the present invention;

FIG. 2B is a top view of one embodiment of the foot, link, tilt bracketand panel clamp assembly according to the present invention;

FIG. 2C is a top perspective view of the cruciform and threaded rodassembly embedded in the foot assembly shown in FIG. 2A;

FIG. 2D is cut away section view of the foot and cruciform assemblyshown in FIG. 2A;

FIG. 2E is cut away section view of the foot and cruciform assembly withthe links, PV panels, tilt bracket, and module clamps shown in FIG. 2A;

FIG. 3A is a perspective view of a panel clamp embodiment according tothe present invention;

FIG. 3B is an exploded view of the panel clamp of FIG. 3A;

FIG. 3C is an exploded view of an alternate embodiment of the panelclamp;

FIG. 3D is a top view of the clamp of FIG. 3C;

FIG. 4A is a perspective view of the panel clamps of FIG. 3A assembledinto a tilt bracket mounted to the top of structural link;

FIG. 4B is a side view showing the panel clamps of FIG. 3A attached tothe solar panels and the tilt bracket;

FIG. 4C is a top view of the panel mounting clamps of FIG. 3A shownattached to the edges of the solar panels in an array;

FIG. 4D is an enlarged view of the clamp attached to a solar panel;

FIG. 4E is an enlarged side view of an alternative embodiment of thepanel clamp for use with panels have an offset lower edge;

FIG. 4F is a side view of the panel clamp and bracket assemblyillustrating the locking tongue on the bottom of the panel clamp;

FIG. 5A is a perspective view of the tilt bracket that is mounted to thetop of the foot assembly;

FIG. 5B is a perspective view of the tilt bracket that is mounted to themiddle of the structural link component;

FIG. 6A is a plan view of a the solar module array in a basicrectangular formation;

FIG. 6B is a plan view of a the solar module array in a geometricpattern having more than four corner areas;

FIGS. 7A-7D illustrate the installation and mounting sequence for asolar panel into the mounting system of the present invention; and

FIG. 8 illustrates the mounting of optional ballast pans onto themounting system of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The following description is provided to enable any person skilled inthe art to make and use the invention and sets forth the best modescontemplated by the inventor for carrying out the invention. Variousmodifications, however, will remain readily apparent to those skilled inthe art. Any and all such modifications, equivalents and alternativesare intended to fall within the spirit and scope of the presentinvention.

FIGS. 1A-1D illustrate the basic components and arrangement of the solararray mounting system according to an embodiment of the presentinvention. FIG. 1A is a perspective view of a solar panel mountingsystem 1 according to an embodiment of the present invention. Fourphotovoltaic solar panels 2 a-2 d are mounted on the mounting structure.The solar panels 2 a-2 d can be “frameless” panels formed as laminatesof two sheets of glass encasing photovoltaic material. For example, thepanels 2 a-2 d may be photovoltaic “thin film” panels. The mountingsystem 1 includes several flexible feet (or “pedestals”) 3 a-3 h. Thefeet 3 a-3 h are the contact points for the system 1 with the mountingsurface (roof or ground). Spanning the distance between the feet and thewidth of two panels 2 a, 2 b or 2 c, 2 d are long links 4 a-4 d. Thelong links 4 a-4 d are preferably installed along a North-South axisdirection. Connecting the feet along the length of a panel arc shortlinks 5 a-5 f, wherein the short links 5 a-5 f are preferably installedalong an East-West axis direction. The long and short links arcpreferably formed from roll steel, which is galvanized or powder-coatedto prevent corrosion. The panels 2 a-2 d are mounted to the feet 3 a-3 hvia tilt brackets 6 a-6 h. At the mid-span of each long link 4 a-4 d, amid-link bracket 7 a-7 d connects to two adjacent panels, 2 a, 2 b or 2c, 2 d. To provide additional support for panels under heavy loads (i.e.snow), center panel supports 8 a-8 h may be mounted on each long link 4a-4 d under the centerline of each panel 2 a-2 d.

FIG. 1B shows a side (end) view of the solar panel mounting system ofFIG. 1A. Note that the solar panel on the left 2 c is mounted higher onthe tilt bracket 6 d and slopes down to mount to the mid-link bracket 7d. Similarly, the right panel 2 d, mounts at the top of the mid-linkbracket 7 d, and mounts to a lower position on its respective tiltbracket 6 h. The angle of tilt for each panel 2 c, 2 d is preferably inthe range of 2°-5°. The center panel supports 8 d, 8 h are preferablysnapped on from the top of the long link 4 d, to provide support to thepanel. The center panel supports 8 d, 8 h preferably have rubber feet toabut against the bottom of the panels. FIG. 1C is a top view of thesystem of FIG. 1A. In a preferred embodiment, the feet 3 a-3 h areapproximately 14 inches square, the long links 4 a-4 d are 6-7 ft. long,and the short links 5 a-5 f are 3-4 ft. long. As discussed below, one ofthe advantages of the present invention is that the size and thicknessesof the linking components can easily be changed to accommodate differentinstallation environments. FIG. 1D further illustrates a 4×2 roof topinstallation. The mounting system's modular design allows it to beeasily adapted to different installation size requirements.

FIG. 1E illustrates an alternate embodiment of the solar mounting systemof the present invention. As shown, each panel is supported by four feetand four links. In this embodiment, note that there are no mid-linkbrackets, and the feet may be connected using links of a similar size.Such a configuration may be desired in installations having very heavypotential loads. FIG. 1F shows a panel array configured according to theembodiment of FIG. 1E.

FIG. 1G illustrates another alternate embodiment of a solar panelmounting system. In this embodiment, the flexible feet 9 a-9 f may beformed as longer elements effectively spanning two links (i.e. 10 a and10 c). The channel formed in the feet between links may itself have alink (i.e. 11 d, 11 f, 11 g, and 11 h) or the channel may be empty asshown in feet 9 a and 9 d. A tilt bracket is installed at each linklocation in the feet 9 a-9 f. Multiple mid-link brackets 12 a-12 f maybe installed on the links in each row, such that, for example, fourpanels are supported between feet elements 9 a, 9 b. In addition, crosslinks 11 a, 11 e can connect feet row-to-row. In another variation, thefeet of the embodiment of FIG. 1G may be formed as the separate feetillustrated in the previous embodiments, and the feet connected withlinks as described above.

The construction of a foot 3 a is shown in greater detail in FIGS.2A-2E. An enlarged view of a foot 3 a is shown in FIG. 2A. The foot 3 ais preferably formed of to rubber or other flexible material. The top ofthe foot contains two perpendicular slots for attaching the long linksand short links. A tilt bracket is located generally in the center ofthe foot (FIG. 2B; top view). In a preferred embodiment, the foot 3 aincludes an upper 20 and lower 21 cruciform, as shown in FIG. 2C. Thecruciforms are preferably formed from stainless steel. As shown incross-section in FIG. 2D, the lower cruciform 21 is mounted to thebottom of the rubber foot, and the upper cruciform is attached to thetop of the foot, generally aligned with the perpendicular slots. Acenter bolt 22 attaches the upper and lower cruciforms 20, 21 to thefoot. The lower cruciform 21 preferably fits in an indentation shapedlike the cruciform in the bottom of the foot. Alternatively, thecruciforms 20, 21 could be molded into the foot at the time the foot ismanufactured. Four threaded rods or studs protrude through thecruciforms and foot to provide attachment points for the long and shortlinks. The links are attached to the threaded rods with washers andnuts. For the embodiment of the feet in FIG. 1G, the feet may be formedwith a set of cruciforms on each end.

In an alternative embodiment, the foot may be formed with a cement orother similar material rigid base, with a rubber upper section toconnect to the links. This may eliminate the need to use the cruciforms.In another alternate embodiment, the foot may be formed with only onecruciform, but the threaded rods have a much larger diameter tocounter-act any bending forces.

As described, the mounting system acts like an integrated net—sharingthe loads when forces pull up on any part of the system. Specifically,the rubber feet act as “nodes” that are able to flex as forces pull thelinks outward. However, the two cruciforms provide strength and rigidityto maintain system integrity. The long links to take the down pushforces on the solar panels from the wind and snow, and flex at eachnode. In addition, the modular design allows the system to be installedon an undulating roof, since the rubber feet can adjust to variations inthe mounting surface.

As shown in FIGS. 2A and 2E, the long links (i.e. 4 a) are normallytaller in cross-section that the short links (i.e. 5 a), since the longlinks are spanning a greater distance under load. Thus, the steel boltsthrough the foot are necessarily longer for the long links than for theshort links. In assembly, the cruciforms 20, 21 and a tilt bracket (i.e.6 a) are attached to the foot with the center bolt 22. Then the longlinks (i.e. 4 a) and short links (i.e. 5 a) are attached to the footusing the threaded rods with the washers and nuts. Note that the longlinks and short links abut the tilt bracket 6 a and overlap the extendedbracket sections (see FIG. 5A). With such a modular construction, theentire mounting system can be pre-configured before any panels areattached to the system.

FIGS. 3A and 3B illustrate a panel clamp according to a preferredembodiment of the present invention. As noted earlier, existing mountingsystems have difficulty mounting to a frameless panel, and especially topanels made from two sheets of glass. The present clamp 30 is designedto mount such frameless panels to the mounting system of the presentinvention. The panel clamp 30 includes two main body parts—an uppersection 31 and lower 32 section preferably made of cast aluminum. Theseclamp part sections 31, 32 are held together by a threaded fastener 34that is inserted through the top section 31 and threaded into the bottomsection 32 of the clamp 30. The fastener 32 is preferably a stainlesssteel bolt having 5/16-18 threads. The interface between the assembledclamp halves (clamp “faces”) and the module edge is filled by a flexiblegasket material 33. In one embodiment of the invention, the flexiblegasket is made from Ethylene Propylene Diene Monomer (EPDM) rubber. Thismaterial has small, finger-like protrusions that allow for easyinsertion onto the module edge, but makes it more difficult to removethe clamps from the module once installed. The panel clamp 30 ispreferably about 4 inches wide and 1 inch high.

In an alternate embodiment, the panel clamp upper and lower sectionscomprise molded polymer resin that is resistant to the effects ofsustained outdoor exposure. These polymer parts have the clamping edgeof the assembly over-molded with a flexible rubber material that createsa better grip on the module material which is typically glass.

On each side of the panel clamp 30 is a mounting post 310, 311. Themounting post 310, 311 engages the tilt bracket or mid-link bracket asdescribed below. The mounting post 310 may be formed as part of theupper 310 a and lower 310 b sections, respectively. The mounting posts310, 311 are formed similarly to bolt or screw heads, having a largerouter lip or “head” and an inner “collar” 312 of smaller diameter. In analternate design, the mounting posts may comprise a separate metalelement, formed with a head and collar on each end, and held in placebetween the upper 31 and lower 32 sections. In a preferredconfiguration, each mounting post 310, 311 has the upper and lowerportions (edges) of each “collar” 312 of the mounting post flattenedoff, in order to help prevent rotation of the clamp in a bracket once itis installed.

An alternate panel clamp design is illustrated in FIGS. 3C and 3D. Asshown in FIG. 3C, the panel clamp 35 includes an upper section 36 and alower section 37. Those sections 36, 37 may be formed out of plastic andconfigured to “snap” fit or glued together. Other materials may be used,and the two sections may be held together by a threaded bolt aspreviously described. The upper section includes two slots 361, 362spaced to engage the tilt and mid-link bracket openings. Similarly, thelower section includes slots 371, 372 aligned with the slots 361, 362 inthe upper section. A mounting axle (rod) 38 is held in a half channel373 in the lower section 37, and a similar half channel (not shown)formed in the upper section 36. The axle 38 is held in position by theupper 36 and lower sections 37, and is generally perpendicular to theblots. A grommet 39 is positioned between the clamp sections to grip thepanel, and may be constructed as noted above.

FIG. 3D shows the assembled clamp, and the axle 38 exposed through theslots. In operation, the panel clamp 35 is lowered into a bracket suchthat the axle 38 engages the mounting openings (described in detailbelow) in a bracket.

As described herein, the panel clamp comprises two pieces. However, theclamps may be molded as single pieces as well.

While specific preferred mounting clamps have been described herein,other panel mounting structures may be utilized with the present system,as long as the mounting structures are configured to interface with themounting openings in the tilt and mid-link brackets.

Once the mounting system has been assembled, the mounting clamps areattached to the photovoltaic panels. Two clamps are attached to each(long) side of a panel at a quarter distance point on each edge, asshown in FIGS. 1A and 1C. FIGS. 4A, 4B and 4C illustrate two panelclamps attached to a mid-link bracket in an isometric view, side viewand top view, respectively. One clamp 41 attaches to the mid-linkbracket at a side position via its mounting posts, effectively makingthe panel edge lower than the other side. Similarly, a second clamp 42attaches to a top of the mid-link bracket via its mounting posts. Alocking cap 44 may, be slid over the top of the top clamp 42 to helpprevent uplift forces from disengaging the clamp 42 from the bracket 43.The locking cap 44 can be configured to slide over the bracket 43, whichalso helps keep the bracket from spreading open under loads. The lockingcap 44 may be formed from metal with the sides bent down, and ain-facing lip on each edge (i.e. forming a block “C” in profile). Eachside has a lip to engage the bracket and slides over the top of thebracket to lock into position.

The mid-link bracket 43 preferably slides onto a long link from thebottom, and engages pre-formed holes in the long link. For example,square holes can be punched into the long links to engage indented tabs431, 432 punched into the mid-link bracket 43.

FIG. 4D is an enlarged side view of the panel clamp 30 attached to asolar panel. Note that the “fingers” of the rubber grommet material areangled such that the clamp can more easily slide onto a solar panel, butresists the removal of the clamp in the reverse direction. Thisembodiment is suitable for panels where the top and bottom sheets ofglass are aligned.

In certain solar panels, the bottom sheet of glass is 0.5 inch or sonarrower than the top sheet to allow for the electrical wiring and/orconnectors. The panels are formed such that the glass sheets are flushon one edge, and offset on the other. Thus, on one edge of the panel thepanel clamps need to account for this offset. As shown in FIG. 4E, in analternate embodiment, the rubber grommet 33 may be formed with arectangular filler block 331 to fill in the gap in the edge of thepanel.

In addition, as shown in FIG. 4F, the panel clamps are preferably formedwith a locking tongue 321 on the bottom of the clamp to engage tabs onthe tilt and mid-link brackets (as described below).

A detailed view of the tilt bracket is shown in FIG. 5A, and a detailedview of the mid-link bracket is shown in FIG. 5B. Note that the tophalves of both brackets are generally similar in construction, with themain differences on the lower halves of the brackets. The brackets arepreferably formed from sheet metal as unitary pieces.

In FIG. 5A, the tilt bracket comprises two symmetric sides 50, 51. Onthe top of each side is a mounting opening 52, 53 for a panel clampmounting post. Behind each mounting opening 52, 53 is a notch 522, 532for engaging the clamp. The bracket includes a tab 521, 531 on each sideof the top to lock the locking cap (not shown) into place. A front faceof each side 50, 51 has an angled edge 510, 511, which helps guide apanel clamp into the lower mounting openings 54, 55 during installation.Each lower mounting opening 54, 55 include a catch 541, 551 to guide andsecure the panel clamp into place. The lower mounting openings 54, 55are deep enough to allow some horizontal movement of the panel clamp inthe bracket to facilitate some movement and alignment of a panel duringinstallation. Each side also includes a locking tab 56, 57 to engage alocking tongue 321 on a panel clamp. Any upward forces on a panel willcause the panel clamp to try and lift up. However, due to the engagementof the panel clamp with the locking tabs 56, 57, the upward force isdistributed through the mounting system via the bracket.

The tilt bracket, as discussed above, is mounted to a foot. The longlinks engage front 60 and rear 61 extensions, while the short linksengage the side extensions 58, 59. The overlapping of the links with theextensions provided for load sharing between the elements. In order toimprove the element-to-element grounding of the metal components, eachextension includes a lip 601, 611, 581, 591 to “bite” into the links andinsure a solid metal-to-metal ground connection.

As noted above the construction of the upper half of the mid-linkbracket is similar to the construction of the upper half of the tiltbracket. As shown in FIG. 5B, the mid-link bracket comprises twosymmetric sides 70, 71. On the top of each side is a mounting opening72, 73 for a panel clamp mounting post. Behind each mounting opening 72,73 is a notch 722, 732 for engaging the clamp. The bracket includes atab 721, 731 on each side of the top to lock the locking cap (not shown)into place. A front face of each side 70, 71 has an angled edge 710,711, which helps guide a panel clamp into the lower mounting openings74, 77 during installation. Each lower mounting opening 74, 77 include acatch 741, 751 to guide and secure the panel clamp into place. The lowermounting openings 74, 75 are deep enough to allow some horizontalmovement of the panel clamp in the bracket to facilitate some movementand alignment of a panel during installation. Each side also includes alocking tab 76, 77 to engage a locking tongue 321 on a panel clamp. Anyupward forces on a panel will cause the panel clamp to try and lift up.However, due to the engagement of the panel clamp with the locking tabs76, 77, the upward force is distributed through the mounting system viathe bracket.

The mid-link bracket, as discussed above, is mounted to a long link, andpreferably snaps into place from the bottom of the link. Thus, the lowerportion of the mid-link bracket is configured to conform to the size andshape of a long link. The top portion of the mid-link bracket isrecessed 701, 711 to insure a tight fit around the long link. Inaddition, alignment and grounding tabs 702, 703, 713 (one not shown)preferably engage in square holes pre-punched into the long link. Again,to improve metal-to-metal contact for grounding the front and rear (notshown) of the link channel include a lip 78 to improve grounding.

As mentioned earlier, one of the advantages of the present mountingsystem is that the size and lengths of the long and short links may beadjusted as needed for particular installations. For example, in colderclimates with winter snows and high winds, the links may need to bestronger to support the increased loads. In a standard implementation,the long links are approximately 1⅝″×2¾″ in cross-section and the shortlinks are 1⅝″×1″. However, to support heavier loads, the links may beformed out of a heavier gauge steel. In order to reduce, costs, though,the entire mounting system may not need to be made out of the thickersteel. Specifically, the long and short links may have a uniformexternal profile, but varied strength depending on a location within apanel array, or the links may have different cross-sections fordifferent applications.

For example, in a standard rectangular roof top installation asillustrated in FIG. 6A, the strongest wind uplift forces are present atthe corner panels (black checked rectangles). Since many installationsmust accommodate roof features such as HVAC equipment, vents, etc. manypanel assemblies have more than four “corners”, as shown in FIG. 6B.Moderate uplift forces are present along the edges (hashed rectangles),while the interior panels (white rectangles) experience relatively loweruplift forces. With this understanding of the relative wind forces atdifferent sections, the mounting system can be constructed accordingly.For example, the long and short links can be constructed out ofrelatively heavy gauge steel for the perimeter panels, and from thinner(and hence cheaper) steel for the interior panels. The respective linkscan be color coded for easy identification by installation personnel.

Once the four panel clamps are installed on a solar panel, the panel islifted into position over two tilt brackets as shown in FIG. 7A. Next,the mounting posts of the panel clamps are aligned with the lowermounting openings in the front of each tilt bracket, and the panel isset into place, as shown in FIG. 7B. The panel is then lowered towardsthe two mid-link brackets as illustrated in FIG. 7C. Finally, the panelis slid forward into the tilt brackets, and then the panel clamps arealigned and set into the mid-link brackets (FIG. 7D). Note as describedabove, the lower mounting openings in the tilt brackets have enoughdepth to allow the panel to slide into the bracket, which helps lock thepanel in place. A locking cap is then applied to the top of eachmid-link bracket to lock the respective panel clamps in place.

If additional system ballast is needed for a particular installation,ballast pans 81, 82, 83, such as shown in FIG. 8, may be added to thesystem between adjacent long links. Ballast can then be placed in thepans 81, 82, 83 to provide additional weight to the system. Differentarrangements and configurations of the ballast pans can be deployed asnecessary.

In environments where the system may be subjected to significant loads,such as heavy snow, additional feet can be placed under to the mid-linkbrackets to provide additional support. In this configuration, the feetare not necessarily attached to the mid-link brackets, but provideadditional load bearing support points for the system.

Those skilled in the art will appreciate that various adaptations andmodifications of the just described preferred embodiments can beconfigured without departing from the scope and spirit of the invention.Therefore, it is to be understood that, within the scope of the appendedclaims, the invention may be practiced other than as specificallydescribed herein.

1. A photovoltaic module mounting system comprising: a plurality offeet, each foot formed at least partially from a flexible material,wherein each foot comprises: a rubber body having two perpendicularslots on a top surface; and at least one metal cruciform attached to therubber body; a tilt bracket attached to each foot; a plurality of metalfirst links connecting the feet together in an axis of a firstdirection; a plurality of metal second links connecting the feettogether in an axis of a second direction; wherein the feet, first linksand second links form an integrated grid for mounting photovoltaicmodules.
 2. The mounting system of claim 1, wherein the foot comprisestwo metal cruciforms, wherein one cruciform is attached to a bottomsurface of the rubber body, and a second cruciform is attached on the atop of the body in the two perpendicular slots.
 3. The mounting systemof claim 2, wherein each foot further comprises a plurality of threadedrods to connect the first and second links to the foot.
 4. The mountingsystem of claim 3, wherein the tilt bracket is bolted to the foot on topof the second cruciform.
 5. A photovoltaic mounting system comprising: aplurality of feet, each foot comprising: a rubber body having twoperpendicular slots on a top surface; and two metal cruciforms, whereinone cruciform is attached to a bottom surface of the rubber body, and asecond cruciform is attached on top of the rubber body in the twoperpendicular slots; a tilt bracket attached to each foot, wherein thetilt bracket comprises: an upper mounting opening; a lower mountingopening; an angled front edge, located between the upper and lowermounting openings; and four extensions which align with the respectiveslots of a respective foot, each extension having a lip to engage alink; a plurality of metal first links connecting the feet together in afirst direction; a plurality of metal second links connecting the feettogether in a second direction; and wherein the feet, first links andsecond links form an integrated grid for mounting photovoltaic modules.6. The mounting system of claim 5, further comprising: at least onemid-link bracket connected to a first link between the feet, themid-link bracket comprising: an upper mounting opening; a lower mountingopening; an angled front edge, located between the upper and lowermounting openings; and a mounting channel having a lip on each end toengage a link.
 7. The mounting system of claim 5, further comprising atleast one center panel support connected to each first link betweenfeet.
 8. The mounting system of claim 5, further comprising a footarranged under each mid-link bracket.
 9. A photovoltaic systemcomprising: a photovoltaic mounting system comprising: a plurality offeet, each foot comprising: a rubber body having two perpendicular slotson a top surface; and two metal cruciforms, wherein one cruciform isattached to a bottom surface of the rubber body, and a second cruciformis attached on top of the rubber body in the two perpendicular slots; atilt bracket attached to each foot, wherein the tilt bracket comprises:an upper mounting opening; a lower mounting opening; an angled frontedge, located between the upper and lower mounting openings; and fourextensions which align with the respective slots of a respective foot,each extension having a lip to engage a link; a plurality of metal firstlinks connecting the feet together in a first axis direction; aplurality of metal second links connecting the feet together in a secondaxis direction; at least one mid-link bracket connected between thefeet, the mid-link bracket comprising: an upper mounting opening; alower mounting opening; an angled front edge, located between the upperand lower mounting openings; and a mounting channel having a lip on eachend to engage a link; wherein the feet, first links and second linksform an integrated grid for mounting photovoltaic modules; and aplurality of photovoltaic modules, each module having four mountingpoints, wherein the mounting points are attached to respective mountingopenings in the tilt and mid-link brackets.